Black Holes
redirect Black hole Black Holes A black hole as defined as being a massive object whose mass is so large that the graviational force it exerts prevents any object that enters a specific distance within it from escaping, except in the case of certain quantum mechanical phenomena. The specific distance from it's center, or it's singularity is known as as it's event horizon. The term hole is really a misnomer as it is not actually a hole in space, merely a place of no return. A black hole is believed to be the end result of a supermassive star collapsing in upon itself. Evolution of a Black Hole The universe is filled with a menagerie of different stars, ranging from medium stars such as ours, to ones significantly smaller and dimmer, to ones much larger and older. A star is basically a combination of two forces. The explosive nuclear force of fusion. Giving us light and heat, and the implosive force of gravity. Implosive in the sense that gravity is a force of attraction, it draws matter towards other bits of matter. A star is a delicate balance of both of these implosive and explosive forces. If a star was too have to great and explosive force in comparison to it's implosive force, it would nova (explode). But if the star was to have a gravitational force that was stronger than its' explosive force it would collapse unto itself. Depending on the mass of the star a variety of things may happen. (Note, the following hypothetical scenario's involve stars which have the same circumference as our sun, if the star has a larger circumference more mass would be needed, if the circumference is smaller, then the opposite is true.) If the star, is say slightly larger than our sun, only up to 1.4 times more massive though, when its nuclear fuel is exhausted and the explosive force decreases drastically, it would begin collapsing unto itself. But then it would suddenly halt. Thanks to the incredible repulsion forces of electrons known as electron degenerancy. The electrons in essence are very claustrophobic and spazz out when confined. As long as the mass is within 1.4 times that of our own sun's this holds true. At this point in time, the force of gravity is counter balanced by this force, as the star becomes what is known as a White Dwarf. But if the star is between 1.5 solar masses (a form of measurement, it's a unit standing for the mass of one of our sun's) and 3 solar masses, something quite different happens. The electron degenerate force is overwhelmed by gravity and it is compressed into another type of star, a neutron star. At this point in time, the force of repulsion is coming not from the electrons, which are undergoing some strange quantum process of compression converting both the protons and electrons into even more neutrons. As it turns out, the repulsive nuclear force comes from the neutrons. And thus the fate of a black hole is avoided. Then there's the final case. When a star is larger than all those masses, with a limited circumference, it has no choice but to collapse unto itself. But what happens there, is a mystery. A final note. Though there are a great deal of stars in the universe, most of the stars, while undergoing the process of collapse, they eject a great deal of matter. In so doing, they in effect avoid becoming black holes. An old latin proverb states "Nature abhors a vacuum." Anatomy of a Black Hole A black hole consists of several different parts, which generally are it's accretion disk, a singularity and an event horizon. Each component has it's own unique properties and is constituted of different things. (A black hole is not limited to just these parts, as shall be discussed later on.) The Accretion Disk The accretion disk is merely a cloud of matter outside of the black hole swirling inward. This matter, as it approaches the black hole reaches unfathomably large speeds, and most of it is actually deflected away from the event horizon. Black holes are borderline anorexic, they only consume 2% of the matter that they come in contact with. Thanks to the speed the matter reaches before the event horizon, it is deflected into 2 separate jets, both perpendicular to the accretion disk. These jets are a large source of magnetic radiation, and emit large amounts of X-rays, not within the visible spectrum. It is through this accretion disk that these black holes are indirectly detected, among other methods. The Even Horizon The event horizon is often symbolized by a pitch black circle, mainly because thats all that can be 'seen'. The even horizon is the point of no return for matter. After that, the force of gravity is so great, that not even light can escape it. But to say that a black hole does not generate radiation is not entirely true. For many years a black hole was considered to not generate radiation on it's own, mainly thanks to its extreme gravity. But, after the advent of quantum mechanics, a loop hole was found in that belief. Thanks to several bits of quantum phenomena all tied together under the title of Hawking Radiation, it was found out that they in fact radiate energy. Though this radiation of energy comes at a price. A black hole radiates infrared light, an almost infintesimal amount, but in so radiating it, it expends it's mass. After several million years, perhaps billion, a black hole will in essence evaporate. All this happening at the edges of the event horizon. The Singularity This would be the must confusing point of the black hole. It is where the mass goes, the stomach of the black hole. But currently there is no theory to explain what exactly is happing at this point, where all the mass of the star is believed to be compressed to about the planck legnth. General Relativity is a theory that specializes in the large, large masses, large distances. Where as Quantum Mechanics is a theory that describes matter when it has a very small mass and is very tiny. The mass at this point is quite large, but the distance is quite small. One can only hypothesize what is actually here.